AssemblyAI vs Knock
Best-in-class speech-to-text API — Universal models, 99 languages, low-latency streaming
vs. Notifications-as-a-service: in-app feeds, email, push, SMS, chat via one API
Pricing tiers
AssemblyAI
Free Credits
$50 in free credits on signup. Full API access.
Free
Pay-as-you-go
Per-hour billing by model. No minimum.
$0 base (usage-based)
Enterprise
Custom contracts. SLA, private deployments, BAA.
Custom
Knock
Developer
Free forever. 10K messages, 500 guide users, 500 AI credits/month.
$0 base (usage-based)
Starter
$250/mo. 50K messages, 2.5K guide users, 2K AI credits. Remove branding.
$250/mo
Enterprise
Custom pricing. White-label, i18n, data warehouse, Datadog, SCIM, SAML, HIPAA/BAA.
Custom
Free-tier quotas head-to-head
Comparing free-trial on AssemblyAI vs starter on Knock.
| Metric | AssemblyAI | Knock |
|---|---|---|
| guide users | — | 2500 users |
| guide users overage | — | $0.05/user USD/user |
| messages monthly | — | 50000 messages/mo |
| messages overage | — | $0.005/message USD/message |
Features
AssemblyAI · 11 features
- Advanced Prompting — Streaming with disfluency + code-switching + realtime diarization.
- Audio Intelligence — Sentiment, topic detection, summarization, entity detection, content safety, IAB…
- Auto Punctuation — Smart capitalization + punctuation.
- Keyterm Prompting — Boost accuracy for domain vocabulary.
- LeMUR (LLM framework) — Run LLMs over transcripts: Q&A, summary, action items.
- Medical Mode — Specialized for clinical + medical vocabulary.
- PII Redaction — Auto-redact credit cards, SSNs, addresses, emails.
- Pre-recorded Transcription — Upload audio/video URL or file → transcript.
- Realtime Streaming — WebSocket-based low-latency STT.
- Speaker Diarization — Identify who spoke when.
- Webhooks — Auto-notify when transcription finishes.
Knock · 13 features
- AI Agents — Autonomous notification drafting & workflow generation.
- Batch + Digest — Group notifications into digests on schedule or window.
- Chat — Slack, Microsoft Teams, Discord.
- Email — Send via SendGrid/Postmark/Resend/Mailgun/AWS SES as relays.
- Guides — In-product messaging, announcements, modals, banners.
- i18n / Localization — Translate templates by user locale.
- In-App Feed — Notification inbox with React/Vue/iOS/Android drop-in components.
- Multi-tenancy — Per-tenant branding, preferences, quiet hours.
- Outbound Webhooks — Subscribe to delivery events.
- Preferences — User + tenant preference center with granular controls.
- Push — iOS (APNs), Android (FCM), Expo, Web Push.
- SMS — Twilio, MessageBird, Telnyx, Vonage as providers.
- Workflows — Visual notification orchestration (branch, batch, delay, throttle).
Developer interfaces
| Kind | AssemblyAI | Knock |
|---|---|---|
| CLI | — | Knock CLI |
| SDK | assemblyai-go, assemblyai (Node), assemblyai (Python), assemblyai (Ruby) | knockapi (Python), knockapi (Ruby), knock-elixir, knock-go, knock-java, @knocklabs/node, @knocklabs/react |
| REST | AssemblyAI REST API | Knock REST API |
| MCP | — | Knock MCP Server |
| OTHER | Streaming WebSocket, Webhooks | Outbound Webhooks |
Staxly is an independent catalog of developer platforms. Some links to AssemblyAI and Knock may be affiliate links — Staxly may earn a commission if you sign up through them, at no extra cost to you. Pricing is verified against vendor pages at publication time — reconfirm before buying.
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